A known approach is disclosed in U.S. Pat. No. 6,159,215, which discloses a method for delivering a vertebral body spacer to the disc space. The instrument has two fingers, which are movable relative to one another and adapted to grip the spacer when the shaft is moved to actuate the fingers. The handle portion includes a grip and a trigger toward the grip for causing the fingers to move toward one another. The fixation is done by way of an extensive linear movement.
Another approach is described in U.S. Patent Application Publication No. 2006/0235426, which discloses an implant, an instrument, and a method for positioning a spinal implant in a spinal disc space between adjacent vertebrae. That implant is fixed by a hinged forceps tip. The forceps tip can be angularly adjusted with respect to the implant, and the instrument is permanently connected to the implant. This approach has a complex instrument locking mechanism instead of a 90° lock/unlock mechanism and it may be impossible to engage the instrument in-situ.
Another approach is disclosed in U.S. Pat. No. 6,066,174, which discloses an implant insertion device including a gripping device on one end. The jaws are movable between the grip position to grasp the implant between the gripping elements and release position to release the implant. A hollow sleeve is slideably disposed over the jaws for forcing the jaws together towards the gripping position. The implant fixation is done with a linear movement of the sleeve, but this linear movement can cause tissue damage and it is not as simple as a 90° locking.
Another approach is described in U.S. Patent Application Publication No. 2004/0153065. The approach is related to an intervertebral implant. The instrument is connected to the implant by a hinge element. The rotation of the axial sleeve of the instrument case is an axial movement of the shaft. This movement is pivoting about the spacer. It may be difficult to engage the instrument is-situ. Angulation is mainly possible in only one direction. The engagement/disengagement mechanism may be complex and uncomfortable.
Another approach is U.S. Patent Application Publication No. 2005/0096745, which discloses an implant for the transforaminal intercorporal fusion of lumbar vertebral column segments. The attachment part to the instrument is configured as a slot. Within this slot, the instrument can be engaged. The instrument can be fixed in different angles with respect to the implant. The interface is a friction lock, which has inferior stability compared to a positive lock. The fixation is done by a thread mechanism. The engagement/disengagement mechanism is less desirable than a 90° locking mechanism because of the used working steps.
Another approach is disclosed in European Patent No. EP1841385B1, which discloses an implant for the transforaminal intercorporal fusion of lumbar vertebral column segments. The attachment part to the instrument is configured as a revolute joint. Within the revolute joint, there is a threading as an interface to the instrument. The instrument can be fixed in different angles with respect to the implant. The interface is a friction lock, which may have reduced stability compared to a positive lock. In addition, in-situ engagement is not possible due to the threading. The fixation of the implant to the instrument is more difficult compared to a 90° locking instrument.